Metal pan acoustical ceiling



INVENTOR.

Sept. 7, 1965 G. c. ADAMS METAL PAN ACOUSTICAL CEILING 4 Sheets-Sheet 1 Filed Jan. 24, 1963 z Wm Sept. 7, 1965 G. c. ADAMS 3,204,383

METAL PAN ACOUSTICAL CEILING Filed Jan. 24, 1963 4 Sheets-Sheet 2 10 27 j; L 1 g E Q INVENTOR.

6076 fi m GJL fl g z.

Sept. 7, 1965 G. c. ADAMS METAL PAN ACOUSTICAL CEILING 4 Sheets-Sheet 3 INVENTOR. George C, fl 7d711$ Mel 7 awlvz'ysi Filed Jan. 24, 1965 United States Patent 3,204,383 METAL PAN ACOUSTICAL CEILING George C. Adams, 3055 Hunting Valley Drive, Ann Arbor, Mich. Filed Jan. 24, 1963, Ser. No. 253,596

14 Claims. (Cl. 52-404) This invention relates to new and useful improvements in overhead ceiling constructions having metal ceiling pans and more particularly to a ceiling construction of this type wherein the components thereof are uniquely formed and interconnected to provide an effective fire barrier.

Overhead ceilings of the type here under consideration have general utility but are used most extensively in industrial and commercial buildings. As conventionally put together, these ceilings are attractive and relatively inexpensive; but they are not particularly effective as a fire barrier. Both the metal pans and the T-bars or other members which carry the pans expand when exposed to high temperatures, and expansion causes the affected parts to warp or buckle. As a result, joints between the pans open up, and in many instances the pans are displaced and perhaps even fall out of the ceiling. In any event, the effectiveness of the ceiling as a fire barrier is reduced if not destroyed as fire easily penetrates the ceiling and damages the floor above, frequently resulting in structural failure.

An important object of the present invention is to provide a metal pan overhead ceiling that is uniquely constructed to provide an effective fire barrier.

Another object of the invention is to provide a ceiling of the above-mentioned character having pan-carrying T-bars that are uniquely constructed to withstand expansion forces which develop in the event of fire.

Still another object of the invention is to provide a ceiling construction of the above-mentioned character having means for holding the pans securely in the structure in the event of fire while at the same time permitting both the pans and the pan supporting members to expand or go in the event the ceiling is exposed to high temperature fire conditions.

Yet another object of the invention is to provide an overhead ceiling construction of the above type that is uniquely constructed to retain fire and heat in the space below the ceiling and that is effective to inhibit penetration of the ceiling by fire and heat sufficiently to reduce' fire risks and therefore insurance costs in buildings equipped with said ceilings. Ideally, the construction should permit standard A.S.T.M. test fire ratings to be obtained.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the drawings forming a part of this specification and wherein like numerals are employed to designate like parts throughout the same:

FIGURE 1 is a fragmentary, perspective view showing a metal pan overhead ceiling construction embodying the invention;

FIGURE 2 is a side elevational view looking in the direction of the arrows 2-2 in FIGURE 1 and showing two T-bar sections connected together by a splicer according to the present invention;

FIGURE 3 is a transverse sectional view taken on the line 3-3 of FIGURE 2;

FIGURE 4 is a vertical sectional view taken on the line 4-4 of FIGURE 1 and particularly showing the manner in which the T-bars are connected to the carrier members; 7

FIGURE 5 is a vertical sectional view taken on the line 5-5 of FIGURE 1 and particularly illustrating one 3,204,383 Patented Sept. 7, 1965 manner in which the metal ceiling pans are fastened to the T-bars;

FIGURE 6 is a vertical sectional view taken on the line 6-6 of FIGURE 1 and showing a modified form of fastener for attaching the metal ceiling pans to the T-bars;

FIGURE 7 is a vertical sectional view taken on the line 7-7 of FIGURE 6 and further illustrating the metal pan connector of FIGURE 6;

FIGURE 8 is a vertical sectional view taken on the line 8-8 of FIGURE 1 and showing still another form of connector for attaching the metal ceiling pans to the T-bars;

FIGURE 9 is a vertical sectional view showing a modified connection between the T-bars and the carrier members;

FIGURE 10 is a vertical sectional view taken on the line 10-10 of FIGURE 9;

FIGURE 11 is a vertical sectional view showing a preferred manner in which a selected one of the ceiling pans is securely but removably fastened in place from below the ceiling;

FIGURE 12 is a fragmentary, vertical sectional view showing still another form of fastener for attaching the metal ceiling pans to the T-bars;

FIGURE 13 is a fragmentary, vertical sectional view taken on the line 13-13 of FIGURE 12;

FIGURE 14 is a fragmentary, vertical sectional view similar to FIGURE 12 but illustrating the manner in which the metal pan fastener shown in FIGURE 12 is utilized and adapted at a light trolfer;

FIGURE 15 is a fragmentary, horizontal sectional view looking in the direction of the arrows 15-15 in FIG- URE 14;

FIGURE 16 is a fragmentary, top plan view of the ceiling showing a novel snorkel device for use in air conditioned buildings;

FIGURE 17 is a fragmentary, vertical sectional view taken on the line 17-17 of FIGURE 16;

FIGURE 18 is a fragmentary, top plan view similar to FIGURE 16 but showing a modified form of snorkel; and

FIGURE 19 is a fragmentary, vertical sectional view taken on the line 19-19 of FIGURE 18.

Considered in certain of its broader aspects, the metal pan overhead ceiling of this invention comprises a plurality of laterally spaced carrier members suspended in any suitable or conventional way from the overhead deck or roof structure of the building. A plurality of laterally spaced T-bars are disposed below and transversely of the carrier members, and they preferably are fastened to the carrier members so that both the carrier members and the T-bars normally are held rigidly and securely against movement relative to each other. Metal ceiling pans are snapped into the T-bar grooves in the conventional way and sound-absorbing pads are placed in the pans.

In order for the ceiling to be an effective fire barrier, it is necessary to tie the metal pans to the T-bars, and this is done according to the present invention by means of tie members which extend over the T-bars and through openings in the side flanges of the pans above or adjacent the top surface of the sound-absorbing pads.

In order to fasten the last pan in the ceiling and to provide an access opening to the space above the ceiling, at least one pan is fastened to the T-bars by a special tie member which extends through a bottom opening in the pan and is fastened in such a way that the fastener is accessible from below the ceiling for removal of the pan.

Referring now to the drawings which show a preferred form of the invention, it will be observed that carrier members 16 are in the form of metal channels placed on edge and suspended by suitable wire hangers 18 from an overhead deck or roof 20. Disposed below the carrier members 16 and fastened securely thereto are T-bars 22 which retain metal ceiling pans 24. As perhaps best shown in FIGURE 5, the T-bars 22 are of formed sheet metal and are of a conventional shape. Each T-bar 22 has a flat top portion 26 and at each side, of the top portion 26 the metal strip from which the T-bar 22 is formed is bent back sharply upon itself to provide lateral lip portions 32 and 34. At the inner sides of the lip portions 32 and 34,.the metal is bent downwardly and inwardly to define tapered sides 28 and 30. Adjacent the lower edges thereof, the sides 28 and 30 converge as shown in the drawings and at about the point of convergence the sides are formed with outwardly rolled bead portions 36 and 38 which receive and retain correspondingly rolled beads on the flanges 46 of the pans 24. Below the beads 36 and 38, the sides 28 and 30 extend outwardly and downwardly to provide divergent edge flanges 40 and 42.

' In this connection it will be observed that the ceiling pans 24 are rectangular in form, and the usual practice is to make the pans twice as long as they are wide. The bottoms 44 of the pans 24 are perforate to give an acoustical effect to the ceiling. An upstanding flange 46 is provided at each of the four sides of the pan, and as suggested each flange is provided with an outwardly rolled bead 48. In practice, the T-bars 22 are spaced apart a distance equal to the length of the ceiling pans 24, and the pans are installed by inserting the end flanges 46 thereof between the edge flanges 40 and 42 of the T-bars until the beads 48 of the pans enter and. are retained by the beads 36 and 38 of the T-bars. The peripheral edges of the pans 24 are beveled as at 50 and the bottoms 44 thereof are bisected by medial grooves 52 which match the bevels 50. Thus, when a plurality of the pans 24are assembled side by side in a ceiling, they have the appearance from below of squares of acoustical tile. To enhance the acoustical qualities of the ceiling provided by the bottom perforations, a pad or overlayment 54 of mineral wool or the like is placed in each of the pans and the pad usually is spaced slightly from the pan by a wire grid 56. The latter provides a space between the pad 54 and the pan 24 which enhances the acoustical effect and also prevents the perforations in the. pans from being filled with paint and closed when theceiling is painted.

In many, if not most, commerical installations, the T-bars 22 are not sufliciently long to span the ceiling, and, under these conditions, it is necessary to connect two or more T-bar sections end-to-end. According tothe present invention, the T bar sections preferably are fastened together by connectors or splicers 58. The splicers 58 preferably are made of sheet metal and they are generally U- shaped in transverse section, as best shown in FIGURE 3. Each splicer 58 has a fiat top portion 60 of sufficient width to span the top 26 of a T-bar section and depending side flanges 62 and 64 which extend down alongside the T-bar flanges 28 and 30. Preferably, the width of the connectors 58 is such that the T-bar sections are relative ly closely received between the connector flanges 62 and 64. Each of the flanges 62 and 64 is cut or divided as at 66 at spaced points along its length, and in practice select ones of the tabs formed by the cuts 66' are bent under the T-bar lip portions 32 and 34 to crimp the connector 58 securely to the T-bar sections joined thereby. A satisfactory practice is to bend alternate tabs under the lip portions 32 and 34. This leaves every other tab on the connector 58 depending at right angles to the top 60 thereof to strengthen and reinforce the connector and the joint between the T-bar sections. Also, the top portions 60 of the connectors 58 preferably are formed with longitudinal ridges or beads 68- to further strengthen and rigidify the connector 58. As shown in FIG. 2, the T-bar sections preferably are spacedapart to leave an expansion gap 70 therebetween. When the ceiling is installed, the splicers 58 bridge the expansion clearance gaps 70 between. adjacent T-bar sections, and they overlap the terway, will cause the channels to bend or roll.

, 4 minal end portions of the connected sections sufficiently to assure a strong rigid joint. From the foregoing, it will be apparent that the crimped tabs of the connectors 58 frictionally hold the T-bar sections to normally prevent relative movement between the sections and in effect to provide rigid unitary T-bar members.

If possible, the T-bars 22 are engaged with and fastened directly to the carrier channel member 16. It is desirable in this type of construction to fasten the T-bars 22 to the carrier member 16 in such a way that the latter are held rigidly and so that the T-bars cannot normally move relative to the carrier members. The usual practice in ceilings of this type is to fasten one or more of the pans 24 in such a way that it can be readily removed to provide an access opening to the space above the ceiling as it sometimes is necessary for workmen to enter this space for inspection purposes or to replace or repair electrical connections and fixtures or to inspect and repair piping or other equipment disposed in or accessible from this space. It i customary for workmen entering the space above the ceiling to lay a plank or other bridging member across a plurality of the carrier channels in order to distribute the weight of workmen and equipment used by them over a plurality of supporting members. The channel members 16 usually are made from relatively light gauge metal, and, if the carrier members are not rigidly held, any lateral thrust exerted by the workmen either directly against the channels or through the plank walk- If this happens, the T-bars 22 may be flexed or warped so that the ceiling pans are bent and either released or offset in some manner to adversely affect the appearance of the ceiling and its effectiveness as a fire barrier.

According to the present invention, the carrier members 16 are normally and preferably fastened rigidly and securely to the T-bars 22 by saddle clips 72 which are uniquely formed and fastened in such a way that they maintain the integrity of the ceiling and its effectiveness as a fire barrier.

As perhaps best shown in FIGURE 4, the saddle clip 72 is made of sheet metal and it has a middle portion 74 of inverted U-shape which fits over and snugly receives one of the carrier channel members 16. At the ends of the portion 74 are lateral outward extensions 76 and 78 which overlay a T-bar 22 at opposite sides of the member 16. Flanges 80 on and depending. from both sides of the extensions 76 and 78 straddle the T-bar and relatively close y receive the lateral lip portions 32 and 34 thereof.

In practice,- the T-bars 22 of course are assembled prior to the ceiling pans 24 and at that time, they are held against the carrier channel members 16 in any suitable or conventional manner while the saddle clips 72 are applied. All of the parts are then held closely together while the flanges 80 are bent under and crimped against the lip portions 32 and 34 of the T-bars. This arrangement provides a firm rigid support for the carrier channel members 16 and normally holds the T-bars 22 securely connected to the carrier members to provide a strong rigid supporting framework for the metal ceiling pans 24.

In some special situations, as for example where recessed light fixtures are mounted in the ceiling as shown in FIGURES 9 and 10, it may be necessary to suspend the T-bars 22 a substantial distance below the channel carrier members '16. As shown in the drawing, conventiona light troifers 88 are available which snap into the T-bars 22 in the same manner as the ceiling pans. These light troifers 88 usually have considerable depth and when they are present, it may be necessary to use a modified clip 90 to fasten the T bars 22 to the carrier channel members 16. Other fixtures, constructions or conditions of course also may require the use of the modified clips 90.

As shown in the drawings, the modified clip 90 comprises a strap-like hanger 92 having a reversely bent portion 94 of inverted; U-shapeat the upper end thereof which wraps around and relatively snugly receives the carrier member 16. Suitable aligned holes are p ovided in the hanger 92 and the end of the U-shaped portion 94 to receive a suitable fastener such as a nail 96 which holds the clip attached to the carrier channel member 16. When a nail is used as the fastener, it is simply pushed through the holes in the hanger and the projecting end thereof is bent as shown to hold it in place. Other suitable forms of fasteners such as cotter pins, for example, also may be used. At its lower end, the hanger strap 92 is formed with a lateral extension 98 which overlays the T-bar 22, and depending flanges 100 formed at the sides of the extension 98 snugly receive and confine the T-bar. At assembly, the flanges 100 are bent under the lateral lip portions 32 and 34 of the T-bar 22 in the same manner and for the same purpose as the flanges 80 of the clip 72 first described.

Tests have shown, however, that the above construction and features alone will not necessarily assure the effectiveness of the ceiling as a fire barrier. In addition, it is necessary to tie the metal pans 24 in some way to the mounting and supporting structure and preferably to the T-bars 22. As a practical matter, the tie member must of course be effective to hold the ceiling pans 24 in place under high temperature fire conditions and they also must be formed to permit quick and easy application thereof during installation of the ceiling so as not unduly to increase the time required to install the ceiling and consequently the cost of installation. Also, the tie members must connect with the pans in a manner that will not interfere with placement of the overlayment pads 54.

One form of tie member that has been found particularly satisfactory in this regard is shown at 104 in FIGURES 1 and 5. The tie clip 104 preferably is made of spring steel wire and is generally of U-shape. The tie clip 104 is adapted to straddle the T-bar 22 and the bight portion 106 thereof is somewhat longer than the width of the T-bar so that the leg portions 108 and 110 thereof are spaced from the side edges of the T-bar. At the terminal ends thereof, the legs 108 and 110 are formed with lateral extensions 112 which are adapted to be received in openings 114 in the flanges of the ceiling pans 24. As shown in the drawings, the openings '114 preferably are in the form of horizontally elongated slots and they of course are located adjacent the attached ends of the pans 24 so as to receive the connecting ends of the tie clips 104. Also, the slotted openings 114 are disposed adjacent to the free edges of the flanges so that the tie clip connections do not interfere with placement of the overlayment pads 54.

At assembly, the ceiling pans 24 are disposed side by side and the slotted openings 114 of adjacent flanges 46 register with each other so that each end of each tie clip 104 fastens two ceiling pans 24. The elongated slots 14 compensate for variations in size of the T-bars 22, ceiling pans 24 and tie clips 104 due to manufacturing tolerances or other causes. In this connection it will be readily appreciated that while these parts must of necessity be held relatively closely to size, they are not precision made parts and there may be sufficient variation in the actual dimension of the parts so that the elongated slotted openings 114 assure proper positioning thereof with respect to the tie clips 104 and assure easy engagement of the clips with the pans 24.

In order to provide a snap-in engagement of the attaching ends 112 with the pans 24, the ends 112 .are bent upwardly as at 115 and thence laterally at 116. Also, the bight portion 106 is formed with a laterally extending U-shaped spring section 118 which permits some flexing of the legs 108 and 110 in applying the tie clips 104 to the pans 24. In practice, the clips 104 are placed over the T-bars 22 and the ends thereof are simply snapped into the openings 114 by rolling the clips slightly and pushing the end portions 116 thereof through the openings 114. Once the ends 112 are fully inserted in the openings 114, the pans 24 are retained securely by the cupped inner portions of the ends 112.

The tie clip 104 is versatile and easily adapted to the different situations that occur inevitably in ceiling constructions. For example, where there are ceiling pans 24 at only one side of a T-bar 22, as at an edge of the ceiling or adjacent to a light trolfer 88, the ends of the clips remote from the pans are simply bent under the projecting lip of the T-bar as shown by broken lines in FIGURE 5.

Another form of spring clip that has been found satisfactory for holding the ceiling pans 24 is shown in FIG- URES 6 and 7. This clip is made of a suitable spring metal and has a flat top portion 122 adapted to overlay and extend transversely across the T-bar, as shown in FIGURE 1. At opposite ends of the top portion 122 and at one side thereof are depending leg portions 124 and 126 which straddle the T-bar 22. Each leg 124 and 126 is split vertically at substantially the middle and from the lower or free end thereof, and the two leg sections 128 and 130 thus formed are in each instance bent in opposite directions so that they are disposed in downwardly diverging relation. As shown in FIGURE 7, the terminal portions 131 and 132 of the leg sections 128 and 130 are bent inwardly toward and across each other. In their final bent position, the terminal portions 131 and 132 preferably extend at an angle of substantially 45 with respect to the plane of the legs. The clip has the advantage that it can be attached to the ceiling pans 24 at assembly simply by pushing the crossed end portions 131 and 132 downwardly against the upturned edges of the pan flanges 46. This pressure causes the leg sections 128 and 130 to spring apart and as the terminal portions 131 and 132 move downwardly on the flanges 46 they snap into the clip retaining openings 114.

As suggested, it is desirable and in most instances necessary to make at least one of the ceiling pans readily removable to provide an access opening to the space above the ceiling. The removable pan 24 may be any selected pan in the field and it preferably is fastened as shown in FIGURE 11. More particularly, elongate threaded studs 138 extending through suitable holes 139 provided in the overhanging lip 32 of the T-bar 22 and fastened thereto by threaded clips 140 also extend through aligned holes 141 in the pan 24. The studs 138 are adjustable as to length by turning them in the clips 140, and in practice they are adjusted so that the lower ends thereof project downwardly through the holes 141 after the pan 24 has been snapped in place just far enough to re ceive the cap nuts 142. If desired, the latter can be the same color as the ceiling pan and if this is the case they are hardly visible. Moreover, the nuts 142 can be easily and quickly removed to permit easy removal of the pan 24 and ready access to the space above the ceiling.

The pan fastener shown in FIGURES 12-15 can be made inexpensively from sheet metal strip material by conventional stamping and forming operations, and it is uniquely fashioned to easily and quickly attach a pair of metal ceiling pans 24 to a T-bar 22. Moreover, the fastener 150 is versatile and adaptable in delferent situations normally encountered in ceilings of the type here under consideration. It holds the ceiling pans securely under all normal conditions and is particularly effective to hold the pans when they warp or twist and buckle under fire conditions. A particular feature of the fastener 150 is its ability to withstand both positive and negative pressures occurring in the event of an explosion below the ceiling. Shock waves from the explosion strike the ceiling from below and of course exert a considerable upward pressure thereagainst. The pan fasteners must be able to resist this upward pressure if the ceiling is to remain intact and an efiiective fire barrier maintained. Air pressing upwardly against the ceiling passes through the perforations and around the acoustical pads 54 and creates a positive pressure of considerable magnitude in the plenum above the ceiling. The air may even lift the pads 54 as it rushes into the plenum. However, this air cannot escape so readily as it presses the pads 54 downwardly against the pans 24 and thus closes the perforations in the pans. This pressure above the ceiling coupled with a partial vaccum below the ceiling following the explosion tends to hurl the pans out of the ceiling or at least dislodge them from the T-bars. Any substantial dislodgement, disarray or loosening of the pans of course destroys or greatly reduces the effectiveness of the ceiling as a fire barrier.

The fastener 150 is generally U-shaped and is adapted to straddle the T-bar 22. As shown in FIGURE 12, the bight portion 152 of the fastener 150 overlays and extends transversely across the T-bar and the depending arm portions 154 and 156 hang downwardly on opposite sides thereof. Laterally outwardly extending flanges 158 and 160 on the lower ends of the arms 154 and 156, respectively, have longitudinal tabs 162 at one end thereof which extend through the openings 114 in the side flanges 46 of the metal pans 24 attached to the T-bar. Only the tab 162 on the arm 154 is shown in FIGURE 13, but it will be understood that a similar tab is provided on the arm 156. Tabs 164 extending laterally in opposite directions from and in the same plane as the bight portion 152 overlay and align vertically with respective tabs 162.

A U-shaped wire clip 168 connects each fastener 150 to the pans 24 with which it is associated and holds the latter securely connected to the T-bar 22 as shown in FIGURE 12. Specifically, the bight portion 170 of the clip 168 overlays the corresponding portion of the fastener 150 and the arms 172 and 174 thereof extend downwardly through aligned apertures in the tabs 158 and 164.

In the use, the end flanges of the pans 24 are snapped between the T-bar fianges in the conventional manner. A pair of fasteners 150 are then dropped onto the T-bar at opposite sides of the pans and inwardly of the side flanges thereof and slipped along the T-bar to push the tabs 162 through the holes 114. Wire clips 168 are then dropped through the apertures in the tabs 164 and 162 and pushed down fully onto the fastener 150. As perhaps best shown in FIGURE 13, the arm portions 172 and 174 of the clips 168 are sufficiently long to extend past the beads 48 conventionally formed in the upstanding side flanges of the pans 24. The clips 168 are readily removable to disconnect the fasteners 150 from the pans 24 simply by lifting them free of the tabs 162 and 164.

In situations where a light troifer 88 is mounted alongside one of the pans 24 as shown in FIGURE 14 the adjacent side wall of the troifer interferes with normal use of the fasteners 150 and clip 168 as hereinabove described. However, both the fastener 150 and the clip 168 are readily adaptable to this environment simply by bending the leg 156 of the fastener under the T-bar side flange 34 adjacent to the troifer by shortening the leg 174 of the clip 169 with a wirecutter or the like. This arrange- .ment also holds all of the parts securely fastened under all of the conditions of use hereinabove described. The fastener 150 can be made of relatively light gauge metal and is readily bendable to crimp the T-bar flange 34.

In many buildings, air conditioning equipment is located in the space above the ceiling. This space then serves as a pressurized plenum and the refrigerated air enters the room below through the perforations in the metal ceiling pan 24. However, it is difiicult to operate this type of air conditioning equipment and at the same time meet the Fire Underwriters fire test time duration requirements which specify acoustical sound deadening pads 54 of mineral wool or the like in the pans, and, for long time duration fire resistance, require a second or overlayment pad 176 also of mineral wool or other noncombustible material.

The overlayment pad 176 is usually larger in size than the acoustical pad 54 and, as the name implies, it overlays the pad 54 with the opposite marginal edge portions thereof supported directly on and also overlaying adjacent T-bars 22. The two pads 54 and 176 are particularly effective in providing a barrier to fire in the room below the ceiling.

Fire rated ceiling constructions having both the acoustical pads 54 and the overlayment pads 176 are adapted for air conditioning of the type hereinabove described without destroying the eflectiveness of the ceiling as a fire barrier according to the present invention by providing a plurality of readily fusible ventilators in at least certain of the pans 24. In the form of the invention shown in FIG- URES 16 and 17, members 178 hereinto referred to as snorkels, are inserted between the acoustical pads 54 and under the superimposed overlayment pads 176. The snorkel 178 here shown (FIG. 16) and the adjacent side flanges of the pans 24 is generally E-shaped in transverse section to provide laterally spaced vertical channels which bypass the acoustical pads when the snorkel is pushed into the pan 24 beside the pad, and the snorkel preferably is sufficiently long to hold the overlayment and the acoustisnorkels fuse out they permit the overlayment pads 176 to drop down on the T-bars 22 and also permit the laterally compressed acoustical pads 54 to expand into the space formerly occupied by the snorkels so that both pads are fully available and in position to perform a proper fire protective function. However, in normal use the snorkels 178 hold the overlayment pads 176 raised sufficiently so that conditioned air can pass freely into the spaces between the pads 65 and 176 and downwardly through the channels 180 to the space below the pads 54 and thence downwardly into the room through the perforations in the pans 24.

Manifestly other forms of snorkel or snorkel equivalents can be used and'a typical example of an alternative means is shown in FIGURES l8 and 19. It is there proposed to use a zigzag strip 182 that is pushed down between one side flange of the pan 24 and the acoustical .pad 54 in the same manner as the snorkel 178. However,

' the strip 182 preferably extends the full length or width of the pad 54 and it is positioned so that the zigzag form thereof provides vertical channels 184 which bypass the pad in order to hold the overlayment pad 176 raised as shown in FIGURE 19. There is also provided a clip 186 having a laterally opening U-shaped lower portion 188 which snaps over and fri'ctionally engages an edge flange of the T-bar 22 and an upstanding portion 190 which holds the overlayment pad 176 in a raised position. Both the strip 182 and the clip 186 are of plastic or other low melting material that will fuse out in the event of fire permitting the acoustical pads 54 to expand laterally and the overlayment pads 176 to drop down and perform their fire protection function. However, the clips 186 norm-ally hold the overlayment pads 176 raised in the manner hereinabove described sufliciently to permit air from the pressurized plenum to pass down through the channels 184 in the strips 182 to the space below the acoustical pads 54 and thence downwardly into the room through perforations in the pans 24.

In summarization, it may be stated that a metal pan acoustical ceiling assembled and constructed according to conventional practice simply by snapping the flanges of the pans into the T-bars 22 does not provide an effective fire barrier as the pans and the various supporting members of the ceiling warp and twist under fire conditions which causes pans to drop or hang from the ceiling or otherwise creates openings in the ceiling through which As soon as the metal ceiling is passed by the fire, the latter of course spreads quickly to the floor or other structure above the ceiling. However, actual tests have demonstrated that if the metal ceiling pans and the various supporting members of the ceiling are constructed and assembled according to present invention, the ceiling does provide a truly effective fire barrier that is effective to confine the fire to the space below the ceiling and enables the floor and ceiling construction to secure, by physical fire testing, an assembly fire rating acceptable to Underwriters Laboratories, National Board of Fire Underwriters and State and Municipal Building Departments.

What is claimed is:

1. An overhead ceiling construction comprising a supporting structure including laterally spaced carrier members,

a plurality of laterally spaced T -bars disposed in a common horizontal plane below and extending transversely of said carrier members,

and clips connecting said T-bars to said carrier members,

metal ceiling pans having peripheral upstanding flanges engaged and retained by said T-bars,

sound-absorbing pads in said pans,

and tie members fastening said pans to said T -bars,

said tie members including parts extending through openings in and adjacent to the ends of the flanges of said pans and adjacent to the top surfaces of said sound-absorbing pads.

2. An overhead ceiling construction comprising a supporting structure including laterally spaced carrier members,

a plurality of laterally spaced T-bars disposed in a common horizontal plane below and extending transversely of said carrier members,

and clips connecting said T-bars to said carrier members,

metal ceiling pans having peripheral upstanding flanges engaged and retained by said T -bars,

sound-absorbing pads in said pans,

and tie members fastening said pans to said T-bars,

certain of said tie members including parts extending through openings in and adjacent to the ends of the flanges of said pans and adjacent to the top surfaces of said sound-absorbing pads,

and the tie members associated with at least one of said pans being in the form of studs suspended from said T-bars and extending through openings in the bottom of said pan, and fasteners on the projecting ends of said studs, said fasteners being removable to release said lastmentioned tie members and to permit removal of the pan associated therewith to provide access to the space above said ceiling.

3. An overhead ceiling construction comprising a supporting structure including laterally spaced horizontal carrier members,

a plurality of laterally spaced T-bars disposed in a common plane below and extending transversely of said carrier members,

and clips connecting said T-bars to said carrier members,

metal ceiling pans having peripheral upstanding flanges engaged and retained by said T-bars,

sound-absorbing pads in said pans, and

tie members fastening said pans to said T-bars,

at least one of said tie members being in the form of a threaded stud suspended from said supporting structure and extending through an opening in the bottom of one of said pans, and a cap nut on the projecting portion of said stud.

4. An overhead ceiling construction comprising laterally spaced horizontal carrier members,

a plurality of laterally spaced T-bars disposed in a common horizontal plane below and extending transversely of said carrier members,

at least certain of said T-bars comprising T-bar sections arranged end-to-end splicers connecting and frictionally clampingly engaging said T-bar sections to hold the same normally rigidly in alignment and joined in a unitary assembly,

clips connecting said T-bars to said carrier members, metal ceiling pans having peripheral upstanding flanges engaged and retained by said T-bars,

and tie members fastening said pans to said T-bars.

5. An overhead ceiling construction comprising laterally spaced carrier members,

a plurality of laterally spaced T-bars disposed in a common plane below and extending transversely of said carrier members,

said T-bars comprising T-bars sections arranged end-to-end,

splicers connecting and frictionally clampingly engaging said T-bar sections to hold the same normally rigidly in alignment and joined in a unitary assembly.

said splicers having top portions overlying the terminal portions of said T-bar section and depending side flanges slotted to define separate flange portions, certain of said flange portions being bent under and frictionally clampingly engaging said T-bar sections and other of said flange portions being spaced from the sides of said T-bar section and disposed substantially at right angles to said top portions to strengthen and stiffen said splicers, clips connecting said T-bars to said carrier members, metal ceiling pans having peripheral upstanding flanges engaged and retained by said T-bars,

and tie members fastening said pans to said T-bars,

said tie members including parts extending through openings in the flanges of said pans,

said openings being adjacent to the ends and the upper edges of said flanges.

6. An overhead ceiling construction comprising laterally spaced, horizontal carrier members, a plurality of laterally spaced T-bars disposed in a common plane below and extending transversely of said carrier members,

clips carried by said carrier members and having laterally extending terminal portions fastened to said T-bars,

metal ceiling pans having peripheral upstanding flanges engaged and retained by said T-bars,

and tie members dctachably fastening said pans to said T-bars.

7. An overhead ceiling construction comprising laterally spaced, horizontal carrier members,

a plurality of laterally spaced T-bars disposed in a common horizontal plane below and extending transversely of said carrier members,

clips connecting said T-bars to said carrier members,

said clips having middle portions of inverted U-shape fitting over said carrier emmbers and laterally extending terminal portions overlying said T-bars and provided with depending flanges bent under and frictionally clampingly engaging said T-bars,

metal ceiling pans having peripheral upstanding flanges engaged and retained by said T-bars,

sound-absorbing pads in said pans,

tie members fastening said pans to said T-bars,

certain of said tie members including parts extending through openings in and adjacent to the ends of the flanges of the pans and adjacent to the top surfaces of said sound-absorbing pads, and

at least one other of said tie members being in the form of a stud suspended from one of said T- bars and extending through an openings in the bottom of one of said pans, a fastener on the projecting end of said stud removable to release said stud and to permit removal of said one pan to provide access to the space above said ceiling.

8. An overhead ceiling construction comprising laterally spaced, horizontal carrier members,

a plurality of laterally spaced T-bars disposed in a common horizontal plane below and extending transversely of said carrier members,

clips connecting said T-bars to said carrier members,

said clips having upper portions fastened to said carrier members and depending hanger portions provided With laterally extending terminal portions,

the latter overlying said T-bars and provided with depending flanges bent under and frictionally clampingly engaging said T-bars, metal ceiling pans having peripheral upstanding flanges engaged and retained by said T-bars, sound-absorbing pads in said pans,

and tie members fastening said pans to said T-bars including parts extending through openings in and adjacent to the ends of the flanges of the pans and adjacent to-the top surfaces of said sound-absorbing pads. a

9. An overhead ceiling construction comprising laterally spaced carrier members,

a plurality of laterally spaced T-bars disposed in a common horizontal plane below and extending transversely of said carrier members,

clips connecting said T-bars to said carrier members,

metal ceiling pans having peripheral upstanding flanges engaged and retained by said T-bars,

sound-absorbing pads in saidpans, and

tie members fastening said pans to said .bars,

said tie members being in the form of wire elements of' inverted U-shape straddling said T- bars and formed with lateral terminal portions on the legs thereof which extend through openings in the pansadjacent to the top surfaces of said sound-absorbing pads. 10. An overhead ceiling construction comprising laterally spaced carrier members, I a plurality of laterally spaced T-bars disposed in a common horizontalp lane' below and extending transversely of said carrier members, clips connecting said T-bars to said carrier members, metal ceiling pans having peripheral upstanding flanges engaged and retained by said T-bars, sound-absorbing pads in said pans, and a tie members fastening said pans to said bars,

said tie members being in the form of wire elements of inverted U-shape straddling said T -bars and formed with lateral terminal portions on the legs thereof which extend through openings in the pans adjacent to the top surfaces of said sound-absorbing pads, the terminal portions of said tie members beingcurved upwardly toward the ends thereof to provide a snap-action connection with said pans. 11. In an overhead ceiling construction including relatively spaced T-bars having side portions provided with bead retainers and metal ceiling pans having end and side flanges formed with longitudinal beads, said end flanges being disposed between the side portions of adjacent T-bars with the beads thereof interfitting and retained by said bead retainers, the improvement comprising formed metal fasteners of inverted U-shape straddling said T-bars and formed with upper and lower tabs extending laterally of the legs thereof, said fasteners being disposed inwardly of the side flanges of said pans with said lower tabs thereof projecting through openings in and above the beads of said flanges,

12 said tabs being provided with aligned apertures in close proximity to the outer sides of said side flanges, and wire clips of inverted U-shape overlaying said fasteners with the legs thereof extending through said apertures. 12. In an overhead ceiling construction including relatively spaced T-bars having side portions provided with bead retainers, and metal ceiling pans having end and side flanges formed with longitudinal beads, said end flanges being disposed between the side portions of adjacent T-bars with the beads thereof received and retained by said bead retainers, the improvement comprising fasteners of inverted U-shape straddling said T-bars and having vertically aligned upper and'lower apertured tabs extending laterally of the legs thereof, said fasteners disposed adjacent to the side flanges of said pans with said lower tabs projecting through openings in said flanges and clips of inverted U-shape overlaying said fasteners with the legs thereof extending through aligned apertures in said upper and lower tabs. 13., In an overhead ceiling construction including laterally spaced T-bars and metal ceiling pans having upstanding end flanges interfitting with and retained by adjacent T-bars and upstanding side flanges extending between said T-bars, the improvement comprising fasteners of inverted U-shape straddling said T-bars and having upper and lower apertured tabs, said fasteners being disposed adjacent to the side flanges of said pans with said lower tabs projecting through openings in said flanges, and clips of inverted U-shape overlaying said fasteners with the legs thereof extending through aligned apertures in said tabs. 14. In an overhead ceiling construction including laterally spaced T-bars andmetal ceiling pans having upstanding end flanges interfitting with and retained by adjacent T-bars and upstanding side flanges extending between said T-bars, the improvement com prising fasteners of inverted U-shape straddling said T-bars and formed with upper and lower apertured tabs, said fasteners disposed adjacent to the side flanges of said pans with said lower tabs projecting through openings in said flanges, and clips of inverted U-shape overlaying said fasteners with the legs thereof extending through aligned apertures in said tabs.

References Cited by the Examiner UNITED STATES PATENTS 2,270,268 1/42 Chambers 20-4 2,580,540 1/52 Graves 18945 2,718,290 9/55 Segil 189-45 2,841,255 7/58 Kemp 189-88 2,921,656 1/60 Goyer l89-88 3,030,670 4/62 Bigelow 50-396 3,038,572 6/62 Becker 18988 HARRISON R. MOSELEY, Primary Examiner. 

6. AN OVERHEAD CEILING CONSTRUCTION COMPRISING LATERALLY SPACED, HORIZONTAL CARRIER MEMBERS, A PLURALITY OF LATERALLY SPACED T-BARS DISPOSED IN A COMMON PLANE BELOW AND EXTENDING TRANSVESELY OF SAID CARRIER MEMBERS, CLIPS CARRIED BY SAID MEMBERS AND HAVING LATERALLY EXTENDING TERMINAL PORTIONS FASTENED TO SAID T-BARS, METAL CEILING PANS HAVING PERIPHERAL UPSTANDING FLANGES ENGAGED AND RETAINED BY SAID T-BARS, AND TIE MEMBERS DETACHABLY FASTENING SAID PANS TO SAID T-BARS. 